The present invention pertains to an overload clutch between first and second rotating parts, with said clutch including a shear element.
U.S. Pat. No. 4,220,019, granted to Mast et al. on Sep. 2, 1980, discloses an overload clutch with a shear pin that extends through opening s in a flange of a shaft and a chain drive sprocket. A catch that can engage with a groove on the circumferential surface of the flange, when the direction of rotation is reversed, is also provided on the sprocket. Due to this measure, it is possible to reverse the drive in order to repair the jamming caused by the shearing of the shear pin.
The problem which the invention aims to solve can be seen in the fact that the flange and sprocket need to be brought into a position where the openings are aligned with one another after shearing of the shear pin so that a new shear pin can be inserted. Since the shaft, as well as the sprocket, are frequently subjected to a load, it is initially required to repair the jammed drive train or to separate a drive connection in order to align the openings.
According to the present invention, there is provided an improved overload clutch of the type including separate rotatable members that are normally interconnected with a shear pin.
A broad object of the invention is to provide a drive connection between two rotating parts which includes a clutch element that is coupled to one of the rotating parts by a shear element where, subsequent to a shear taking place, the clutch element associated with the shear pin can be brought, without being subjected to a load, into a position where a new shear element can be inserted.
A more specific object of the invention is to provide an overload clutch of the type noted above, wherein the two drive parts are interconnected to each other by an overload clutch including a first clutch element fixed to one drive part and a second clutch element fixed to the other drive part by a shear element, with the second clutch element normally being engaged for rotation with the first clutch element but, subsequent to a shear occurring, being easily selectively rotatable relative to the associated drive part to permit the second clutch element and associated drive part to be realigned for allowing the insertion of a new shear element.